[Tutor] List vs. Set:

[Mark Lawrence]

On 24/02/18 20:00, James Lundy wrote:
> To whom it may concern. This code is from Dr. John Keyser.

Please arrange for him to go on a programming course :-)

> 
> 
> gooddata = []
> 
> for singleday in datalist:
>      if (singleday[0] == day) and (singleday[1] == month):

Yuck, unneeded brackets disease.

>          gooddata.append({singleday[2], singleday[3], singleday[4], singleday[5]})

That looks like a set to me.

> 
> # Perform analysis
> minsofar = 120
> maxsofar = -100
> numgooddates = 1
> sumofmin = 0
> sumofmax = 0
> 
> # so singleday in datalist is a list while singleday in gooddata is a set?????????

Seems like it.

> 
> for singleday in gooddata:
> 
>      sumofmin += singleday[1]
>      sumofmax += singleday[2]
>      if singleday[1] < minsofar:
>          minsofar = singleday[1]
>      if singleday[2] > maxsofar:
>          maxsofar = singleday[2]
> 
> Could this be a bug in my Pycharm 3 compiler I have had mixed experiences running the code.

I very much doubt that.

> 
> An insertion of a space after for singleday in gooddata: line 54 caused the program to run as desired, once, since other runs cause the error

Really, I don't see how?

> 
> 
> Traceback (most recent call last):
> 
>    File "C:/Users/Dad/PycharmProjects/TopDownDesign/WeatherDataSpecialDay.py", line 56, in <module>
> 
>      sumofmin += singleday[1]
> 
> TypeError: 'set' object does not support indexing
> 
> persist.
> 
> I will attach the code and test file. Please allow me to thank you in advance for answering this query. I am new with Python and would appreciate any advice.

Put print calls into the code that you don't show above.  This should 
show what gets written to the datalist and it's type, ditto for the 
gooddata list.  I think you'll find that the code "works" when an 
invalid day and month gets input, yet produces the traceback when a 
valid day and month is input.

> 
> God Bless:
> 
> James Lundy
> jalundy at computer.org<mailto:jalundy at computer.org>
> 

-- 
My fellow Pythonistas, ask not what our language can do for you, ask
what you can do for our language.

Mark Lawrence